ka1axy:Free things often come with a catch. In this case:its fog signal sounds for three seconds twice a minute as needed.

I have this feeling that "as needed" is decided by some wet behind the ears night shift government lackey in Washington, DC who has a button he pushes whenever the mood strikes him. He has no idea what it does, but at 3 or 4 in the morning, idling away in his cube, he hits the button 50 times, wondering why the hell it's on his desk.